Blender Cycles Jagged Edges On Basic Shapes
For future reference, the general preference here is to use Blend Exchange

I think this is a combination of anti-aliasing and the very fine angle and sharp contrast. Which is why even at high quality settings of 300% and 1000 samples in your file, it is still happening.

Here I see it (when zoomed out a bit):



Here I don't (100% scale). Or at least it is hard to detect without my eyes going funny: 

I would suggest that the filter (anti-aliasing) needs adjusting for this sort of scene. Have you tried playing with the Render/Film/Pixel Filter values? I found that 2.0 looks better and 2.5 is the best. More than that and it starts to get fuzzy.

Quality is sufficient at maybe 64 render samples, which makes testing lot quicker than with the 1000 that you have. Using a Render Region (under Scene/Dimensions panel) to restrict rendering to the bit you are interested in also helps a lot with speed of testing.

This is 300%, 64 samples, pixel filter = 2.5, viewed at 100% (press 1 in render window):